Preparation, structural characteristics and antioxidant activity of polysaccharide and its metal chelates from the peel of Dioscorea oppositifolia L

Abstract

Two metal chelates of Dioscorea oppositifolia L. peel polysaccharides (DTP) were prepared: iron chelate (DTP-Fe) and zinc chelate (DTP-Zn). The physicochemical properties of the polysaccharide and its metal chelates were assessed by UV-Vis absorption spectroscopy, Fourier-transform infra-red spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Antioxidant activities were evaluated by DPPH, ABTS + and hydroxyl radical scavenging assays. According to ICP-MS, the iron content of DTP-Fe was 9.47%, while the zinc content of DTP-Zn was 4.02%. The antioxidant capacity of DTP-Fe increased with the increase of concentration, and its overall activity was higher than that of DTP and DTP-Zn. This polysaccharide-iron chelate can be developed and utilised as an antioxidant and multifunctional iron supplement. DTP-Zn showed the potential to be a natural antioxidant and zinc supplement food.

Graphical Abstract

Keywords:

• Polysaccharides of dioscorea oppositifolia L. peel
• iron chelate
• zinc chelate
• physicochemical properties
• antioxidant activities

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The Key Scientific and Research Projects of Higher Education Institutions in Henan under Grant (23A230006). The Henan province scientific and technical tackle-key-problem plan (232102110117). Natural Science Foundation of Henan Province (232300421127). Project of academic support for top talents in Anhui province (gxbjZD2022106). Key projects of natural science research in universities of Anhui Province (KJ2019A1236, KJ2021A1297).